ALDRICH AND DARLINGTON, 99 



central ; one presutural ; three supra-alar; two scutellar (pairs) ; one 

 inesosternal ; two fronto orbital ; two sternopleiiral ; no prescutellar. 



Head rounded, eyes round ; antennae short, third joint slightly 

 elongated, with short, hare aiista ; face moderately receding, epis- 

 toma ascending between the small vibrissse, with a distinct edge. 

 Thorax with sparse and coarse hairs, besides the bristles. Wings 

 with first vein short, and the auxiliary pale and thin, difficult to 

 perceive, yet ending separate from the first vein. 



Type. — Oregona. 



On account of the comparative shortness and indistinctness of 

 the auxiliary vein, it' may be thought that Siligo is not a true Helo- 

 myzid genus; after comparing it with numerous genera in Sapro- 

 myzidse, Geomyzid^e, etc., we are satisfied that its nearest relation- 

 ships are here. It is very unlike Curtonotnm. 



While the course of the suture over the middle of the dorsum is 

 not very apparent, either in this or Helomyza, the indications are 

 that in Helomyza there is only one bristle before the suture, while 

 here there are two, and only three behind. 



TABLE OF SPECIES. 



Bristles all yellow oregona n. sp. 



Bristles all black litorea u. sp. 



^iiligo oregona Aldricb, n. sp., PI. IV, figs. 1, 7. 



Length 2.8 mm. ; of wing, the same. 



Yellow. All the hairs and bristles yellow, except the spines of the oosta, 

 which are black. 



Head entirely yellow ; eyes of medium size, round ; antennse yellow ; ari.sta of 

 medium size, only microscopically pubescent; ocellar bristles very long; cheeks 

 somewhat inflated, about the width of the eye. 



Thorax entirely straw yellow, dorsum sparsely pubescent; scutelium entirely 

 yellow, bare except the ordinary four bristles; mesopleura bare except one large 

 and two small yellow bristles at the upper posterior corner; propleura bare 

 except the one propleural bristle; sternopleura besides the two long bristles on 

 the upper edge with rather sparse pubescence. 



Abdomen grayish-yellow, hypopygium of the male small and inconspicuous, 

 but armed with a slender black filament turning back. 



Wings hyaline, veins yellow; spines of the costa black, rather long and promi- 

 nent. 



Legs entirely straw-yellow; a row of rather strong bristles on the under side 

 of the fore femur; tarsal claws black except at base. 



Three males, two females. Aldrich : Hood River, Oregon, July. 



The head in oregona is more produced downward than in litorea, 

 but the difterence is almost wholly in the cheeks ; in oregona the epis- 

 toma extends upward between the vibrissee farther than in litorea. 



TRANS. AM. KNT. SOC. XXXIV. MARCH. 1908. 



